Telluric acid is a colorless crystal, which is prepared by the reaction of sulfuric acid and barium tellurite or by oxidizing elemental tellurium with a strong oxidant. It is stable in air and can be used to prepare other telluric acid and tellurite as well as as an oxidant. Tellurium is oxidized to telluric acid with strong oxidant. There are two variants: monoclinic and cubic. The density of monoclinic is 3.071g/cm3, and that of cubic is 3.17g/cm3. It is easily soluble in water and hardly soluble in concentrated nitric acid. It is heated at 100 ℃ to 200 ℃ to dehydrate to produce intermediate product (H2TeO4) n, and finally it is completely transformed into anhydride TeO3. It is a weak acid similar to carbonic acid.